The present invention relates to a camera shake detection apparatus for performing shake detection using an optical/processing system of a focusing detection device.
Focus detection of a phototaking lens of a camera is conventionally performed by various methods. Such methods comprise a method for detecting an out-of-focus state of an object image at a position conjugate to the film plane, or a method for detecting the phase difference between two images formed by light beams from two different regions of a phototaking lens.
U.S. Pat. No. 4,218,119 describes an apparatus for detecting shake of an image due to movement of the object or handshaking utilizing a photodetector which is primarily used for focus detection. However, this apparatus adopts a focusing method for focusing in accordance with the degree of the out-of-focus state of an image. For this reason, it takes a relatively long period of time to stabilize the object lens at a prescribed position. In addition, shake detection can only be performed after proper focusing is established. Thus, it takes a relatively long period of time before a shutter is actuated after shake detection is performed.